Exposure device and image forming device

Abstract

To provide an exposure device capable of maintaining appropriate image quality.SOLUTION: An image forming device includes a panel member 12a facing a photoreceptor and having a plurality of light emitting elements 41. The panel member 12a has a plurality of element groups in which a plurality of light emitting elements 41 are arranged in a main scanning direction S along the rotation axis of the photoreceptor. In the element group, the light emitting elements 41 adjacent to each other in the main scanning direction S are disposed such that the positions in the sub-scanning direction H orthogonal to the main scanning direction S are shifted from one end side to the other end side toward one side in the main scanning direction S. When one end side light emitting element arranged at one end in the sub-scanning direction H and the other end side light emitting element arranged at the other end in the sub-scanning direction H adjacent to each other in the main scanning direction S expose corresponding pixels, density correction for reducing the density of the pixels is performed.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an exposure device and an image forming apparatus that include a panel member having a plurality of light-emitting elements. [Background technology]

[0002] Conventionally, electrophotographic image forming apparatuses have been widely used, which form an electrostatic latent image on a photosensitive member using a laser beam or the like, and then develop, transfer, and fix the electrostatic latent image to form an image on paper. In recent years, linear light sources, in which point light sources such as light-emitting elements are arranged in a line, have been used as the light source for exposing the photosensitive member. Also, a method has been proposed in which a plurality of light-emitting elements are arranged not only in the main scanning direction but also in the sub-scanning direction to increase the amount of exposure and the pixel density (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-193235 Summary of the Invention [Problem to be solved by the invention]

[0004] A conventional image forming apparatus forms an electrostatic latent image by controlling the light emission of a light source device including a plurality of light-emitting element rows each configured with a plurality of light-emitting elements arranged in the sub-scanning direction, and includes an image information acquisition unit that acquires image information of the electrostatic latent image, a light source control unit that sequentially controls the light emission of the plurality of light-emitting elements based on the image information, an error information acquisition unit that acquires information indicating an error in the direction in which the light-emitting elements are arranged with respect to the sub-scanning direction, and an adjustment value generation unit that generates an adjustment value for the light emission amount of the light-emitting elements. In this image forming apparatus, the light emission amount of light-emitting elements with small installation errors is increased to prevent degradation of image quality.

[0005] However, in order to achieve higher definition and lower power consumption, it is sometimes difficult to arrange light-emitting elements in a line or in a matrix, and they are sometimes arranged with a periodic offset in the sub-scanning direction. When arranged in this manner, when light-emitting elements that are far apart in the sub-scanning direction expose adjacent pixels, a phenomenon known as reciprocity failure occurs, resulting in a problem of higher density than expected.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide an exposure device and an image forming apparatus that can maintain appropriate image quality. [Means for solving the problem]

[0007] The exposure device according to the present disclosure is an exposure device comprising a panel member facing a photosensitive body and having a plurality of light-emitting elements, wherein the panel member has a plurality of element groups in which the plurality of light-emitting elements are arranged in a main scanning direction along the rotation axis of the photosensitive body, and in the element groups, the light-emitting elements adjacent to each other in the main scanning direction are arranged such that their positions in a sub-scanning direction perpendicular to the main scanning direction are shifted from one end to the other end as they move in one direction of the main scanning direction, and the exposure device is characterized in that when a pixel corresponding to a one-end light-emitting element arranged at one end in the sub-scanning direction and an other-end light-emitting element arranged at the other end in the sub-scanning direction, which are adjacent to each other in the main scanning direction, is exposed, a density correction is performed to lower the density of the pixel.

[0008] The exposure device according to the present disclosure may be configured to reduce the light intensity of the corresponding light-emitting element during the density correction.

[0009] The exposure device according to the present disclosure may be configured such that, in the density correction, when exposing consecutive pixels in the sub-scanning direction, the light intensity of the light-emitting element on one end side and the light intensity of the light-emitting element on the other end side are alternately reduced along the sub-scanning direction.

[0010] The exposure apparatus according to the present disclosure may be configured such that, in the density correction, when pixels that are continuous in the sub-scanning direction are exposed, pixels whose density is to be reduced are spaced apart in the sub-scanning direction.

[0011] The exposure device according to the present disclosure may be configured such that, in the density correction, the light intensity of the one end side light-emitting element and the other end side light-emitting element is corrected based on the light intensity of light-emitting elements adjacent to the one end side light-emitting element and the other end side light-emitting element in the main scanning direction.

[0012] The image forming apparatus according to the present disclosure is characterized by including the exposure device according to the present disclosure. [Effects of the Invention]

[0013] According to the present disclosure, when the exposure time difference between adjacent pixels is large, the density of the pixel increases due to a phenomenon known as reciprocity failure, and by correcting this, appropriate image quality can be maintained. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view showing an image forming apparatus according to a first embodiment of the present disclosure. [Figure 2] 1 is a schematic configuration diagram showing an image forming apparatus according to a first embodiment of the present disclosure. [Figure 3] FIG. 2 is a schematic plan view showing a panel member according to the first embodiment of the present disclosure. [Figure 4] FIG. 10 is a characteristic diagram showing the relationship between exposure time difference and density. [Figure 5] 10 is a characteristic chart showing an example of image data before and after density correction. [Figure 6] 10 is a characteristics chart showing an example of image data before and after density correction in the second embodiment of the present disclosure. [Figure 7] 13 is a characteristics chart showing an example of image data before and after density correction in the third embodiment of the present disclosure. [Figure 8] 13 is a characteristic chart showing an example of image data before and after density correction in the fourth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015] (First embodiment) Hereinafter, an image forming apparatus according to a first embodiment of the present disclosure will be described with reference to the drawings.

[0016] FIG. 1 is a schematic cross-sectional view showing an image forming apparatus according to a first embodiment of the present disclosure.

[0017] The image forming device 100 is a multifunction device having a copy function, a scanner function, a facsimile function, and a printer function, and transmits an image of a document read by the image reading device 130 to an external device, and forms an image of a document read by the image reading device 130 or an image received from an external device in color or monochrome on a recording medium such as paper.

[0018] An original transport device 110 that is supported so as to be able to open and close freely is provided above the image reading device 130. The original transport device 110 transports one or more originals one by one. The image reading device 130 scans a scanning optical system 130b to read an original placed on an original placement table 130a, or reads an original transported by the original transport device 110 to generate image data.

[0019] The image forming apparatus 100 is provided with a fixing device 1, a developing device 2, a photosensitive drum 3 (an example of a photosensitive body), a drum cleaning device 4, a charger 5, an intermediate transfer belt device 7, a secondary transfer device 11, an exposure device 12, and a paper feed section 18.

[0020] Image forming apparatus 100 handles image data corresponding to color images using black (K), cyan (C), magenta (M), and yellow (Y), or monochrome images using a single color (e.g., black). Image forming apparatus 100 is provided with four developing devices 2, four photosensitive drums 3, four drum cleaning devices 4, and four chargers 5 for forming four types of toner images, and four image stations Pa, Pb, Pc, and Pd are configured corresponding to black, cyan, magenta, and yellow, respectively.

[0021] The charger 5 uniformly charges the surface of the photosensitive drum 3 to a predetermined potential. The exposure device 12 has a panel member 12a facing the surface of the photosensitive drum 3, and exposes the surface of the photosensitive drum 3 to light to form an electrostatic latent image. The development device 2 develops the electrostatic latent image on the surface of the photosensitive drum 3 to form a toner image on the surface of the photosensitive drum 3. The drum cleaning device 4 removes and collects residual toner on the surface of the photosensitive drum 3. Through the series of operations described above, a toner image of each color is formed on the surface of each photosensitive drum 3. The panel member 12a will be described in detail later with reference to FIG. 3.

[0022] The intermediate transfer belt device 7 includes an intermediate transfer roller 6, an endless intermediate transfer belt 71, an intermediate transfer drive roller 72, an intermediate transfer driven roller 73, and a cleaning device 9. Four intermediate transfer rollers 6 are provided inside the intermediate transfer belt 71 so as to form four types of toner images corresponding to each color. The intermediate transfer rollers 6 transfer the toner images of each color formed on the surface of the photosensitive drum 3 onto the intermediate transfer belt 71, which moves around in a circular motion.

[0023] The intermediate transfer belt 71 is stretched over an intermediate transfer drive roller 72 and an intermediate transfer driven roller 73. In the image forming apparatus 100, the toner images of each color formed on the surface of each photosensitive drum 3 are sequentially transferred and superimposed to form a color toner image on the surface of the intermediate transfer belt 71. The cleaning device 9 removes and collects waste toner remaining on the surface of the intermediate transfer belt 71 without being transferred to paper.

[0024] The secondary transfer device 11 sandwiches and transports a sheet of paper transported through the paper transport path 21 in the transfer nip portion TN between the secondary transfer roller 11a and the intermediate transfer belt 71. When the sheet of paper passes through the transfer nip portion TN, the toner image on the surface of the intermediate transfer belt 71 is transferred onto the sheet of paper, and the sheet of paper is transported to the fixing device 1.

[0025] The fixing device 1 includes a fixing belt 31 that rotates around an axis and a pressure roller 32. The fixing device 1 sandwiches a sheet of paper onto which a toner image has been transferred in a nip portion N between the fixing belt 31 and the pressure roller 32, and applies heat and pressure to fix the toner image to the sheet. Although not shown in FIG. 1, the fixing device 1 may include components other than the fixing belt 31 and the pressure roller 32.

[0026] The paper feed unit 18 includes a paper feed cassette that holds recording media (paper) used for image formation, and is provided below the exposure device 12. The paper is pulled out of the paper feed unit 18 by a pickup roller 16 and transported to a paper transport path 21. The paper transported to the paper transport path 21 passes through the secondary transfer device 11 and the fixing device 1, and is then discharged to a paper output tray 19 by a discharge roller 17.

[0027] Conveyance rollers 13, registration rollers 14, and discharge rollers 17 are arranged on paper conveyance path 21. Conveyance rollers 13 facilitate the conveyance of paper. Registration rollers 14 convey paper at a speed equal to the process speed at which an image is formed on the paper. Registration rollers 14 are provided between paper feed unit 18 and secondary transfer device 11, and adjust the timing of paper conveyance so that the toner image is transferred to the paper by secondary transfer device 11. For example, registration rollers 14 wait (temporarily stop) while clamping paper conveyed from paper feed unit 18, and then start conveying the paper at a constant speed in synchronization with secondary transfer device 11.

[0028] When an image is to be formed on the back side of the paper in addition to the front side, the conveying direction of the paper is changed by discharge rollers 17, and the paper is conveyed to reversing conveying path 22. In reversing conveying path 22, the paper is guided up to registration rollers 14 in a reversed state by reversing conveying rollers 15. Image forming apparatus 100 forms an image on the back side of the paper guided to registration rollers 14 in the same manner as on the front side, and discharges the paper to discharge tray 19.

[0029] Fig. 2 is a schematic configuration diagram showing an image forming apparatus according to a first embodiment of the present disclosure. Note that Fig. 2 shows only a portion of the image forming apparatus 100, and other members not shown in Fig. 2 may be included as appropriate.

[0030] The panel member 12a has a plurality of light-emitting elements 41. The light-emitting elements 41 are, for example, organic light-emitting diodes (OLEDs) or LEDs. The control unit 50 is a CPU mounted in the image forming apparatus 100, and controls the operation of the image forming apparatus 100, for example, by causing the image forming apparatus 100 to perform density correction, which will be described later.

[0031] FIG. 3 is a schematic plan view showing a panel member according to the first embodiment of the present disclosure.

[0032] The exposure device 12 is provided with four panel members 12a so as to face the four photosensitive drums 3, respectively. Note that the exposure device 12 may be provided independently for each photosensitive drum 3, as long as a panel member 12a is provided corresponding to each of the four photosensitive drums 3. The four panel members 12a have substantially the same configuration, and therefore, in FIG. 3, one panel member 12a is extracted and schematically shown.

[0033] In the image forming apparatus 100, the axial direction of the rotation axis of the photosensitive drum 3 is parallel to the width direction of the paper on which an image is formed, and the photosensitive drum 3 is configured to rotate around the axis of the rotation axis. The panel member 12a is a rectangular flat plate, and its longitudinal direction (main scanning direction S) corresponds to the axial direction, and its lateral direction (sub-scanning direction H) corresponds to the rotation direction of the photosensitive drum 3.

[0034] The panel member 12a has a plurality of element groups (first element group Gr1 and second element group Gr2) in which a plurality of light-emitting elements 41 are arranged in the main scanning direction S. FIG. 3 shows the panel member 12a having the first element group Gr1 and the second element group Gr2 each composed of eight light-emitting elements 41, but this is not limited thereto. The number of light-emitting elements 41 constituting the element groups and the number of element groups provided on the panel member 12a may be changed as appropriate. Hereinafter, in order to distinguish the plurality of light-emitting elements 41, the light-emitting elements 41 may be referred to by being numbered d1, d2, . . . , d16 in order from one end (the left end in FIG. 3) to the other end (the right end in FIG. 3) in the main scanning direction S. That is, the first element group Gr1 is composed of light-emitting elements 41 d1 to d8, and the second element group Gr2 is composed of light-emitting elements 41 d9 to d16.

[0035] In the element group, adjacent light-emitting elements 41 in the main scanning direction S are arranged such that their positions in the sub-scanning direction H are shifted from one end side (the upper end side in FIG. 3) to the other end side (the lower end side in FIG. 3) as they move in one direction in the main scanning direction S. The dashed lines H1 to H8 (first line to eighth line) shown in FIG. 3 are parallel to the main scanning direction S, lined up in the sub-scanning direction H at regular intervals, and indicate their positions in the sub-scanning direction H. In other words, the light-emitting elements 41 arranged on the same line are positioned overlapping each other in the sub-scanning direction H.

[0036] In the panel member 12a shown in Fig. 3, the light emitting element 41 at d1 is arranged on a first line (H1) located at the uppermost end in Fig. 3, and the light emitting element 41 at d2 is arranged on a second line (H2) shifted downward from the first line. The light emitting elements 41 from d3 onwards are also arranged shifted downward in the same manner, and the light emitting element 41 at d8 is arranged on an eighth line (H8) located at the lowermost end in Fig. 3.

[0037] The second element group Gr2 repeats the same arrangement as the first element group Gr1, with the light emitting element 41 at d9 being arranged on the first line (H1), and the light emitting elements 41 at d10 and onwards being arranged shifted downward in order, with the light emitting element 41 at d16 being arranged on the eighth line (H8).

[0038] As described above, the distance between adjacent light-emitting elements 41 in the same element group, for example, the light-emitting element 41 at d2 and the light-emitting element 41 at d3, is one line (1 line difference: 1Ln) in the sub-scanning direction H. However, at the boundary between element groups, the distance between adjacent light-emitting elements 41 at d8 and the light-emitting element 41 at d9, for example, is seven lines (7 line difference: 7Ln) in the sub-scanning direction H.

[0039] The exposure device 12 exposes the light-emitting elements 41 in order from the light-emitting element 41 located upstream in the rotation direction of the photosensitive drum 3, and controls the timing at which the light-emitting elements 41 expose in accordance with the rotation of the photosensitive drum 3. Specifically, in the configuration shown in Fig. 3, the light-emitting elements 41 on the first line (H1), i.e., the light-emitting elements 41 at d1 and the light-emitting elements 41 at d9, are located furthest upstream in the rotation direction of the photosensitive drum 3 and are exposed first. Furthermore, the light-emitting elements 41 on the eighth line (H8), i.e., the light-emitting elements 41 at d8 and the light-emitting elements 41 at d16, are located furthest downstream in the rotation direction of the photosensitive drum 3 and are exposed last.

[0040] Here, if we focus on the light-emitting element 41 d9 (corresponding to the one-end light-emitting element) arranged at one end in the sub-scanning direction H and the light-emitting element 41 d8 (corresponding to the other-end light-emitting element) arranged at the other end in the sub-scanning direction H, although they are arranged adjacent to each other in the main scanning direction S, they are arranged farthest apart among the multiple light-emitting elements 41 in the sub-scanning direction H, and there is a large time difference in exposure timing. If the difference in exposure timing (exposure time difference) is large between adjacent pixels, it will affect the density, so this will be explained with reference to FIG. 4.

[0041] FIG. 4 is a characteristic diagram showing the relationship between the exposure time difference and the density.

[0042] In FIG. 4, the horizontal axis represents the exposure time difference between adjacent pixels, and the vertical axis represents pixel density. As described above, when the exposure time difference between adjacent pixels is large, the pixel density may become high due to a phenomenon known as reciprocity failure. In FIG. 4, point P1 corresponds to the exposure time difference for a one-line difference of 1Ln, and point P2 corresponds to the exposure time difference for a seven-line difference of 7Ln, with point P2 having a higher density than point P1. As such, even if the same settings such as exposure amount are used to achieve the same density, the intended density may not be obtained depending on the arrangement of the light-emitting elements 41.

[0043] In contrast to this, in the present embodiment, density correction is performed to correct the density of pixels in accordance with the arrangement of the light-emitting elements 41, thereby adjusting the density to an appropriate level. Next, density correction will be described with reference to FIG.

[0044] FIG. 5 is a characteristic chart showing an example of image data before and after density correction.

[0045] In the image forming apparatus 100, horizontal and vertical coordinates are set for each pixel of image data to be formed. The horizontal direction X is the width direction of the paper and corresponds to the axial direction (main scanning direction S) of the photosensitive drum 3. The vertical direction Y is the length direction of the paper and corresponds to the rotation direction (sub-scanning direction H) of the photosensitive drum 3. For ease of explanation below, the coordinate in the horizontal direction X may be abbreviated as Xn (n is a natural number), and the coordinate in the vertical direction Y may be abbreviated as Ym (m is a natural number).

[0046] FIG. 5 shows a portion of the image data, with X8 being the coordinate corresponding to the light-emitting element 41 at d8, and X9 being the coordinate corresponding to the light-emitting element 41 at d9, and the value at each coordinate indicates the density of the corresponding pixel. The density is set to a gradation having multiple levels, and in the example shown in FIG. 5, there are 256 levels (gradations). The gradation is set so that the higher the value, the higher the density, and the lower the value, the lower the density. Pixels with a density of 0 correspond to areas that are not colored with toner and are not exposed to light-emitting elements 41. The gradation is not limited to this, and the image data volume may be reduced by converting to fewer levels, such as 16 levels or 4 levels.

[0047] FIG. 5 shows the first image data GD1 before density correction and the second image data GD2 after density correction. In density correction, the density of the pixel combination corresponding to X8 and X9, which have the same coordinate in the vertical direction Y, is corrected based on a preset correction coefficient. As a result, the density at each coordinate in the second image data GD2 is lower than that of the first image data GD1. The exposure device 12 determines the light intensity of the light-emitting element 41 based on the density in the second image data GD2. Thus, when the exposure time difference between adjacent pixels is large, the pixel density becomes high due to a phenomenon known as reciprocity failure. Correcting this phenomenon allows appropriate image quality to be maintained. Furthermore, density can be easily corrected by reducing the light intensity of the light-emitting element 41.

[0048] The correction coefficient may be set appropriately, and for example, the correction amount may be set so that as the density of either X8 or X9 approaches 0, the correction amount decreases, or if the other is 0, the correction amount is set to 0. In other words, the effect of an increase in density due to reciprocity failure increases as the exposure amount increases, and when only one light-emitting element 41 is exposed, there is no effect of reciprocity failure, so it is preferable to set an appropriate correction coefficient so that correction is made based on this.

[0049] (Second embodiment) Next, an image forming apparatus according to a second embodiment of the present disclosure will be described with reference to the drawings. The second embodiment differs from the first embodiment in the content of density correction. Note that the second embodiment has a configuration substantially similar to the first embodiment shown in FIGS. 1 to 5, so a description thereof will be omitted and only the differences will be described.

[0050] FIG. 6 is a characteristics chart showing an example of image data before and after density correction in the second embodiment of the present disclosure.

[0051] Fig. 6 shows the third image data GD3 before density correction and the fourth image data GD4 after density correction. In the example shown in Fig. 6, the density is set to two gradations, and the light-emitting element 41 exposes pixels corresponding to 1 and does not expose pixels corresponding to 0. In other words, when the density is set to two gradations, the light-emitting element 41 is controlled to either emit light or not emit light (non-emission).

[0052] In the third image data GD3, the pixels corresponding to X8 and X9 all have a density of 1. In other words, if we focus only on X8 and X9, the image is a straight line that is two pixels wide and extends in the vertical direction Y.

[0053] In density correction, when consecutive pixels are exposed in the sub-scanning direction H (vertical direction Y), the light intensity of the light-emitting element on one end (for example, light-emitting element 41 at d9) and the light intensity of the light-emitting element on the other end (for example, light-emitting element 41 at d8) are alternately reduced along the sub-scanning direction H, and the pixels whose density is reduced are spaced apart in the sub-scanning direction H. Specifically, the fourth image data GD4 differs from the third image data GD3 in that the densities of the pixel where X8 and Y3, the pixel where X9 and Y8, and the pixel where X8 and Y12 are set to 0. Note that in FIG. 6, pixels in the fourth image data GD4 whose density has changed compared to the third image data GD3 due to density correction are shaded.

[0054] In density correction, the density is accumulated from top to bottom in the vertical direction Y, and when the accumulated value exceeds a threshold, the density of X8 is reduced. After that, the accumulated value is reset, and the density is accumulated again. Then, when the next accumulated value exceeds the threshold, the density of X9 is reduced, replacing X8, whose density was reduced the previous time. In other words, the pixels whose density is reduced alternate between X8 and X9. By repeating this process sequentially, the pixels whose density is reduced can be dispersed so that they do not concentrate locally. In this way, when the exposure range is wide, by dispersing the pixels whose density is reduced, correction can be performed to prevent areas from having extremely low density.

[0055] As described above, when controlling the light-emitting element 41 only between emitting and not emitting light without changing the light amount, a correction may be made to reduce the density of the image by performing a thinning process to disperse and arrange the non-emitting pixels.

[0056] (Third embodiment) Next, an image forming apparatus according to a third embodiment of the present disclosure will be described with reference to the drawings. The third embodiment differs from the second embodiment in the content of density correction. Note that the third embodiment has substantially the same configuration as the first and second embodiments shown in FIGS. 1 to 6, so a description thereof will be omitted and only the differences will be described.

[0057] FIG. 7 is a characteristics chart showing an example of image data before and after density correction in the third embodiment of the present disclosure.

[0058] Fig. 7 shows the fifth image data GD5 before density correction and the sixth image data GD6 after density correction. In the example shown in Fig. 7, the density is set to four levels, and the light-emitting element 41 exposes pixels corresponding to 1 to 3, and the light-emitting element 41 does not expose pixels corresponding to 0. In Fig. 7, pixels in the sixth image data GD6 whose density has changed compared to the fifth image data GD5 due to density correction are shaded.

[0059] In the density correction, as in the second embodiment, pixels for which the density is to be reduced are alternately arranged at X8 and X9. The pixels for which the density is to be reduced have their gradation reduced by one level, and if the gradation is 1, it is set to 0 to prevent the light emitting element 41 from emitting light.

[0060] (Fourth embodiment) Next, an image forming apparatus according to a fourth embodiment of the present disclosure will be described with reference to the drawings. The fourth embodiment differs from the second embodiment in the content of density correction. Note that the fourth embodiment has substantially the same configuration as the first to third embodiments shown in FIGS. 1 to 7, so a description thereof will be omitted and only the differences will be described.

[0061] FIG. 8 is a characteristics chart showing an example of image data before and after density correction in the fourth embodiment of the present disclosure.

[0062] FIG. 8 shows seventh image data GD7 before density correction and eighth image data GD8 after density correction.

[0063] The seventh image data GD7 and eighth image data GD8 shown in Figure 8 include not only the densities corresponding to X8 and X9, but also the density at X7, which is the coordinate corresponding to the light-emitting element 41 at d7, and the density at X10, which is the coordinate corresponding to the light-emitting element 41 at d10.

[0064] In density correction, the light intensity of the light-emitting element 41 at d8 and the light-emitting element 41 at d9 is also referenced, along the main scanning direction S, for the light-emitting element 41 at d7 and the light-emitting element 41 at d10. Specifically, the density is accumulated from top to bottom in the vertical direction Y, including all of X7 to X10, and a determination is made as to whether it exceeds the threshold. Note that pixels whose density is to be reduced are alternately arranged between X8 and X9. In this way, by considering the influence of not only the pixel one pixel away but also the pixel two pixels away, image quality can be adjusted with greater precision.

[0065] It should be noted that the embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present disclosure should not be interpreted solely by the above-described embodiments, but should be defined based on the claims. Furthermore, all modifications within the scope and meaning equivalent to the claims are included. [Explanation of symbols]

[0066] 3 Photoconductor drum (an example of a photoconductor) 12 Exposure equipment 12a Panel member 41 Light-emitting element 50 control section 100 Image forming device S Main scanning direction H Sub-scanning direction

Claims

1. An exposure device including a panel member facing a photosensitive member and having a plurality of light-emitting elements, the panel member has a plurality of element groups in which the plurality of light-emitting elements are arranged in a main scanning direction along the rotation axis of the photosensitive member, In the element group, the light-emitting elements adjacent to each other in the main scanning direction are arranged such that their positions in a sub-scanning direction orthogonal to the main scanning direction are shifted from one end side to the other end side along one side of the main scanning direction, When a one-end side light-emitting element arranged at one end in the sub-scanning direction and a other-end side light-emitting element arranged at the other end in the sub-scanning direction expose corresponding pixels, a density correction is performed to reduce the density of the pixel. An exposure apparatus characterized by:

2. 2. The exposure apparatus according to claim 1, In the density correction, the light amount of the corresponding light emitting element is reduced. An exposure apparatus characterized by:

3. 2. The exposure apparatus according to claim 1, In the density correction, when exposing pixels that are continuous in the sub-scanning direction, the light amounts of the light emitting elements on one end side and the light amounts of the light emitting elements on the other end side are alternately reduced along the sub-scanning direction. An exposure apparatus characterized by:

4. 2. The exposure apparatus according to claim 1, In the density correction, when pixels that are continuous in the sub-scanning direction are exposed, pixels whose density is to be reduced are arranged at intervals in the sub-scanning direction. An exposure apparatus characterized by:

5. 2. The exposure apparatus according to claim 1, In the density correction, the light intensities of the one end side light emitting element and the other end side light emitting element are corrected based on the light intensities of light emitting elements adjacent to the one end side light emitting element and the other end side light emitting element in the main scanning direction. An exposure apparatus characterized by:

6. An image forming apparatus comprising the exposure device according to claim 1.

Images